Wrinkle resistance finish for cellulosic textiles



United States Patent of America as represented by the Secretary ofAgriculture No Drawing. Filed Jarred, 1961, Ser; No.- 115,268 8'Claims.(Cl. 8-1163) (Granted under Title 35, US. Code (1952), sec. 266)- Anon-exclusive, irrevocable, royalty-free license in the invention hereindescribed, throughout the World for all purposes of the United StatesGovernment, with the power to grant sublicenses for such purposes, ishereby granted to the Government of the United States of America.

This invention relates to the finishing of cellulosic textile fabricswhereby the fabric is given improved resistance to wrinkling or mussing,improved shape-holding properties, and the ability to dry smooth afterlaundering. Moreover, the cellulosic fabric so finished may be launderedby procedures usually used with textiles of the same type, whichprocedure can include the use of hypochlorite bleaching agents and acidsours, without sulfering additional damage because of the finish orextensive loss of the improved properties imparted by the finish.

Because of their poor resiliency, cellulosic textiles fabrics, such ascotton and rayon,-tend to become wrinkled in use and acquire a mussed orunpleasant appearance. To overcome this objectionable property, it hasbeen the practice to treat or finish cellulosic textiles with themethylol derivatives of organic nitrogen compounds,-

such as urea, ethyleneurea, guanidine, or melamine. These agents doproduce a finished cellulosic textile that has improved resistance towrinkling or mussing while in use, and in addition, give the textile, toa greater or lesser extend, the ability to dry smooth after laundering.Textiles finished with many of these agents, however, cannot be bleachedwith the usual hypochlorite bleaching agents during laundering withoutthe danger of suffering severe strength loss or discoloration. Inaddition, the souring step common in many laundryprocedures will oftenpartially remove the finish produced by these agents, and causeextensive loss of the imparted properties; Thesedisadvantages ofpresently used finishes are most pronounced with cotton textiles becauseof the more rigorous laundry procedures to which cotton textiles aresubmitted as compared with those which are employed with othercellulosic textiles.

The mechanism by which the agents mentioned produce the wrinkleresistance and smooth-drying properties in cellulosic textiles isbelieved to be a crosslinle'ng of the linear cellulose molecules in thefibrous material. The effect can be accomplished by etherification ofcellulose with-the methylol compound'using an acidic or alkalinecatalyst. To obtain the necessary crosslinking,.the finishing agent mustbe polyfunctional, that is, contain two or more reactive methylolgroups. The agents used, therefore, are di-, tri-, or tetra-methylolcompounds formed by the reaction of an organic nitrogen compound,containing two or more nitrogen containing groups with formaldehyde-in aratio'to give at least one molar equivalent of formaldehyde for eachnitrogenous group. For example, the finishing agent dimethylolethyleneurea is formed from the reaction of ethyleneurea with twomolar-equivalents of formaldehyde. Similarly, the agent trimethylolmelamine is formed from the reaction of melamine with three molarequivalents of formaldehyde. Numerous investigators in this field havereported that similar agents derived from nitrogenous compoundscontaining a single nitrogenous group are ineffective in pro- 3,144,299Patented Aug. 11, 1964' ducing the desired Wrinkle resistance andsmooth-drying properties. The single known exception to'thisis thereaction product of formamide and formaldehyde. ,Accordingly, this agenthas been described by some investigators as actually belonging toanotherclass of agents and producing a nitrogen free finish on the fabric. Onthe other hand, other investigators have reported that this agent givesa finished fabric very susceptible todamage by hypochlorite bleachingagents, a property normally associated with the presence of nitrogen.

The use ofdimethylol dicarbamates as wrinkle resistance finishing agentshas been described. This type of agent, derived from compounds with twocarbamate groups, has the disadvantages previously noted for the agentsin present use. We have found, however, that agents can' be preparedfrom organic monocarbamates, containing a single nitrogenous group, andformaldehyde, and that these agents are effective in producing wrinkleresistance and smooth drying properties in cellulosic textiles.Furthermore, textiles finished with the agents prepared frommonocarbamates are less susceptible to damage from hypochloritebleaching agents and have properties more durable to acidic souring thanthose tiles so treated may be laundered by procedures normally used withuntreated textiles of similar type, which procedure may includethe useof hypochlorite bleaching agents and the use of acid sours in the rinse,without sufiering any deleterious effects because of the treatment ordrastic loss of the properties imparted by the treatment.

The object of this invention may'be accomplished by applying to thetextile a product formed from the reaction of a monocarbamate, such asmethyl carbamate, ethyl carbamate, propyl carbamate, or butyl carbamate,and two moles of formaldehyde. The product is formed by allowing thecarbamate and formaldehyde to react in a slightly alkaline aqueoussolution. After the reaction is completed, the solution is diluted tothe desired concentr'ation for application to the textile and an acidiccatalyst is added to the solution. The concentration of the product tobe used will vary, usually between 5 and 20% of the solution, dependingon the type of textile to be finished. The acidic catalyst can be aninorganic or amine salt of a strong mineral acidf Particularly suitableas catalysts are zinc nitrate and magnesium chloride used as the readilyobtainable hydrates in a quantity 0.5 to 6.0% of the weight of thecarbamate-formaldehyde solution containing the desired concentration ofthe carbamate-formaldehyde condensate.

The solution can be applied to textiles by usual finishing procedures,such as soaking the textile in the solution and padding or centrifugingso that the textile retains a weight of solution equal to 50 to of itsdry weight.

Thewet textile is dried at relatively low temperature, as 60 to C., andthen heated briefly at a higher tem-' may contain other auxiliary agentscommonly used in-textile finishing For instance, wetting agents may bein cluded in the bath to provide more rapid impregnation of the appliedsolution. Softening agents may also be 3 included to modify the hand andfeet of the finished textile.

The properties of textiles finished by the method of this invention areillustrated in the following examples. All parts and percentagesdescribed are by weight. The degree of wrinkle resistance obtained inthe finished textile is shown by the crease recovery angle determined by4 Example 5 Samples treated as described in Examples 1, 2, and 3 weresubjected to launderings in an automatic home type washer usingdetergent and hypochlorite bleach to give 0.02% available chlorine andto 5 launderings as described in AATCC Test 14-53. The properties of thefabrics are tabulated below.

Original After 20 Home Launderings After 5 AATCC Washes Treatment CreaseElmen- Scorch Crease Elmen- Scorch Crease Elmen- Scorch Recovery dorfTear Test, per- Recovery dorITear Test,pcr- Recovery dortTear 'Iest,pcr-

Angle, Strength, cent Angle, Strength, cent Angle Strength, cent W-i-Fg. Warp Strength W+F Warp Strength W-l-F Warp Strength Retained RetainedRetained Example 1 262 480 106 256 307 98 272 487 102 Example 2. 262 480102 247 413 87 254 580 98 Example 3- 268 533 91 256 433 89 252 567 92the American Society for Testing Materials Test D1424- Example 6 5 6T.The resistance of the textiles to hypochlorite bleach is shown by thestrength retained in the American Association of Textile Chemists andColorists Test 69-1952. The tearing strength of the textiles is shown bythe tearing strengths obtained by the Elmendorf method, American Societyfor Testing Materials Test D142456T.

Example 1 (MgCl -6H O) The solution was padded onto a simple of 80x 80cotton print cloth to give a 7080% wet pickup. The wet fabric was driedat original dimensions for seven minutes at 60 C., and then cured atoriginal dimensions for 3 minutes at 160 C. The curing step was followedby an afterwash in Warm water with a nonionic detergent and then tumbledried. The finished fabric possessed a crease recovery angle of 262(warp-i-filling) while an untreated, after-washed sample had a creaserecovery angle of only 187 (warp-l-filling).

Example 2 A sample was treated as described in Example 1, except thatthe solution contained 0.75% hydrated zinc nitrate (Zn(NO -6H O) insteadof magnesium chloride as catalyst. The finished fabric had a creaserecovery angle of 262 (warp-l-filling).

Example 3 A sample was treated as described in Example 1, except that1.5% of 2-amino-2-methyl-l-propanol hydr0 chloride was used as catalystinstead of magnesium chloride. The finished fabric had a crease recoveryangle of 268 (warp-f-filling).

Example 4 A sample was treated as described in Example 1 except that1.5% of emulsified polyethylene was added to the treating bath. Thefinished fabric had a crease recovery angle of 294 (warp-l-filling) anda warp tearing strength of 627 g. by the Elmendorf method. A similarsample prepared as in Example 1 had a crease recovery angle of 262(warp-i-filling) and a Warp tearing strength of 480 g.

For comparison purposes to demonstrate the durability of the finish toan acid sour, a sample treated as described in Example 2 and a sampletreated with water solution of 8% by weight of dimethylol ethyleneureaand 0.75% by weight of hydrated zinc nitrate were immersed in a solutionbuffered to pH 2.2 for 30 minutes at 40 C. The dimethylol ethylcarbamate treated sample retained 94% of its original nitrogen contentand 94% of its original crease recovery angle after its treatment. Thedimethylol ethyleneurea treated sample retained only 22% of its originalnitrogen content and only 62% of its original crease recovery angle.

Example 7 A 15% water solution of a butyl carbamate-torrnaldehydeproduct was prepared in the following manner: butyl carbamate wasdissolved in 7.7 times its weight of water and suflicient 36%formaldehyde solution, which was previously adjusted to pH 8 with sodiumhydroxide, was added to afford a ratio of formaldehyde to butylcarbamate of 2:1. This solution was allowed to stand overnight at roomtemperature. After this time hydrated magnesium chloride was added tomake 4% of the solution and the solution used to treat fabric as inExample 1. The finished fabric had a crease recovery angle of 254(warp-t-filling) and retained 91% of its original strength in the scorchtest.

We claim:

1. A process for treating a cellulosic textile fabric comprising:wetting the fabric with an aqueous solution containing about from 5 to20% by weight of a water soluble product of formaldehyde and a carbamatecompound selected from the group consisting of methyl carbamate, ethylcarbamate, propyl carbamate, and butyl carbarnatc, said product havingbeen produced by the reaction, in aqueous alkaline solution, of theformaldehyde and the carbamate compound in the mole ratio of 2 to 1, andfrom 0.5 to 6.0% by weight based on the weight of the carbamatecompound-formaldehyde solution of an acidic catalyst, and drying andcuring the treated fabric at a temperature of from to C.

2. The process of claim 1 wherein the carbamate compound is ethylcarbamate.

3. The process of claim 1 wherein the carbamate compound is butylcarbamate.

4. The process of claim 1 wherein the acidic catalyst is an inorganicsalt of a strong mineral acid.

5. The process of claim 1 wherein the acidic catalyst is the amine saltof a strong mineral acid.

6. A process for treating a cellulosic textile fabric comprising:wetting the fabric with an aqueous solution containing about from 5 to20% by weight of a water soluble product of formaldehyde and a carbamatecompound selected from the group consisting of methyl carbarnate, ethylcarbamate, propyl carbamate, and butyl carbamate, said product havingbeen produced by the reaction, in aqueous alkaline solution, of theformaldehyde and the carbamate compound in the mole ratio of 2 to 1, andfrom 0.5 to 6.0% by Weight based on the weight of the carbamatecompound-formaldehyde solution of an acidic catalyst selected from thegroup consisting of zinc nitrate hexahydrate, magnesium chloridehexahydrate, and 2-amino-2-methyl-l-propanol hydro chloride, drying thetreated fabric at a temperature of about from to C. for about 7 minutes,and curing the dried, treated fabric at a temperature of from to C. forabout from 3 to 5 minutes.

7. The process of claim 6 wherein the acidic catalyst is zinc nitratehexahydrate.

8. The process of claim 6 wherein the acidic catalyst is magnesiumchloride hexahydrate.

References Cited in the file of this patent UNITED STATES PATENTS OTHERREFERENCES Hackhs Chemical Dictionary, Third Edition,

Merck Index, Seventh Edition, page 1083 (1960).

1. A PROCESS FOR TREATING A CELLULOSIC TEXTILE FABRIC COMPRISING: WETTING THE FABRIC WITH AN AQUEOUS SOLUTION CONTAINING ABOUT FROM 5 TO 20% BY WEIGHT OF A WATER SOLUBLE PRODUCT OF FORMALDEHYDE AND A CARBAMATE COMPOUND SELECTED FROM THE GROUP CONSISTING OF METHYL CARBAMATE, ETHYL CARBAMATE, PROPYL CARBOMATE, AND BUTYL CARBAMATE, SAID PRODUCT HAVING BEEN PRODUCED BY THE REACTION, IN AQUEOUS ALKALINE SOLUTION, OF THE FORMALDEHYDE AND THE CARBAMATE COMPOUND IN THE MOLE RATIO OF 2 TO 1, AND FROM 0.5 TO 6.0% BY WEIGHT BASED ON THE WEIGHT OF THE CARBAMATE COMPOUND-FOROMALDEHYDE SOLUTION OF AN ACIDIC CATALYST, AND DRYING AND CURING THE TREATED FABRIC AT A TEMPERATURE OF FROM 130 TO 160*C. 